1. Technical Field
The present invention relates generally to the field of medicinal herbs, and in particular to systems for extracting and concentrating active ingredients of medicinal herbs.
2. Background Art
In recent years, research in the field of natural drugs has received greater attention world-wide. The World Health Organization and UNESCO have periodically held international conferences on natural drugs. The United States has allocated significant funding for large-scale research on natural products that may be potential sources of anti-cancer drugs. In recent years, Japan has experienced a passion for Chinese herbs.
The international community has attached importance to research in the area of natural drugs for a number of reasons. First, the toxic effects of medications derived from natural products are comparatively few. Further, the human body exhibits comparatively less resistance to natural medications. In addition, sources of natural drugs are relatively abundant, and the time and expense typically required to develop a new drug from natural products is considerably less than that required for developing drugs from non-natural sources.
In the field of natural drug research, particular attention has been devoted to medicinal plants. (As used herein, the terms "herb," "medicinal herb," "plant," and "medicinal plant" are used interchangeably to refer to all herbs and plants, the active ingredients of which can be extracted by boiling in an appropriate medium.) Among all the countries in the world, China is the richest in plant resources, having approximately 35,000 species of higher plants, of which on the order of 5,000 have known medicinal uses. One Chinese text alone, the Ben Tsau Kang Mu, lists over 1,892 varieties of such plants, which are widely used and which can play a significant role in the treatment of various disorders. China has a long history of practicing herbal medicine with a wealth of practical experience spanning several thousands of years. The application of modern scientific technology and methods to further organize, research, and advance the practice of traditional Chinese medicine and the use of Chinese herbal remedies is a task of the utmost importance.
It is known in the art that the active ingredients of herbs can be extracted and concentrated. In a typical prior art approach, the herb or herbs to be processed are first boiled in a suitable extraction medium, such as water or alcohol, resulting in an herbal liquid. The herbal liquid is then placed in a concentration tank in which a heat exchanger is used to heat the herbal liquid. The extraction medium evaporates, leaving an herbal paste that can be processed further, as needed.
There are disadvantages inherent in the prior art process. First, it exposes herbs to high temperatures and pressures which can destroy the herbs active ingredients. Further, the concentration vessel and heat exchanger taught by the prior art produce suboptimal yields of herbal concentrate: a certain amount of concentrate is lost due to foaming, a certain amount of concentrate is burned at the bottom and sides of the concentration vessel, and other concentrate becomes trapped in the heat exchanger.
There is thus a need in the art for a high-yield system for extracting and concentrating herbal compounds without exposing them to unduly high temperatures and pressures.